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Mary C Johnston, MD

Assistant Professor of Psychiatry and Behavioral Sciences
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The Johns Hopkins Hospital

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Call 410-464-6641 (8a.m. to 6p.m., EST, Mon-Fri)

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Call +1-410-502-7683 (7a.m. to 6p.m., EST, Mon-Fri)

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  • Assistant Professor of Psychiatry and Behavioral Sciences


Adult Psychiatry, Forensic Psychiatry, Geriatric Psychiatry, Memory Disorders, Psychiatry, Psychiatry and Behavioral Sciences

Research Interests

Outreach mental health care for homebound elders; Aging in Place; Memory Disorders


Dr. Johnston is is co-investigator of MIND at Home, a study measuring the effectiveness of pro-active care coordination to persons with memory disorders at home. In 2008, the American Association for Geriatric Psychiatry created the AAGP Deirdre Johnston Award for Excellence and Innovation in Geriatric Mental Health Outreach Services, to encourage programs providing mental health services to the frail elderly in their homes.
Dr Johnston''s previous appointment was at Wake Forest University School of Medicine, where she was the inaugural Director of the Kate Mills Snider Geriatric Psychiatry Outreach Program (the GO Program), an innovative model of collaborative in-home mental health care for the frail elderly. The GO Program and the Deirdre Johnston award were made possible by generous gifts from the Snider family of Salisbury NC and New York, in honor of their mother, Kate Mills Snider, in gratitude for Dr Johnstons care of Mrs. Snider.
Dr Johnston holds specialty qualifications in psychiatry in the UK and in Canada as well as in the United States and is certified by the American Board of Psychiatry and Neurology in both Geriatric Psychiatry and Forensic Psychiatry.


  • English

Additional Resources

Additional Resources +
  • Education +


    • University College Hospital (Galway) (1979)


    • University of Alberta - Falculty of Medicine & Dentistry / Psychiatry (Edmonton Alberta) (1989)
    • University College Hospital / Psychiatry (Galway) (1985)


    • Geriatric Psychiatry, American Board of Psychiatry & Neurology (2005)
    • Psychiatry, American Board of Psychiatry & Neurology (1992)
  • Research & Publications +

    Selected Publications

    1. Johnston D: A series of cases of dementia presenting with posttraumatic stress disorder symptoms in WWII combat veterans, Journal of the American Geriatrics Society; 48:70-72. 2000.
    2. Johnston, D and Reifler, BV: The organization and provision of Geriatric Psychiatry Services for the Elderly. In The New Oxford Textbook of Psychiatry, Oxford University Press, 2000.
    3. Johnston D, Jones BN 3rd. Telepsychiatry consultations to a rural nursing facility: A two year experience. Journal of Geriatric Psychiatry and Neurology, 14(2):72-5, 2001.
    4. Jones BN 3rd, Johnston D., Reboussin B, McCall WV. Reliability of telepsychiatry assessments: Subjective versus observational ratings.  Journal of Geriatric Psychiatry and Neurology, 14(2):66-71, 2001.
    5. Johnston D, Eitel D, McCall, W.V. Electroconvulsive Therapy (ECT): An Introduction for Elderlaw Professionals. Elder’s Advisor: The Journal of Elder Law and Retirement Planning, 4(1):18-27, 2002.
    6. Rosenberg P, Johnston D, Lyketsos CG. A clinical approach to mild cognitive impairment. Am J Psychiatry 163:11, Nov 2006.
    7. Johnston, D: Anxiolytics and Neuroloptics in Psychiatric Aspects of Neurologic Diseases: Practical Approaches to Patient Care, eds Constantine Lyketsos, Philip Slavney, Peter Rabins, and John Lipsey. Oxford University Press, in press.
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  • Contact & Locations +


    The Johns Hopkins Hospital
    600 N. Wolfe Street
    Sheikh Zayed Tower
    Baltimore, MD 21287
    Phone: 410-955-6158
    Appointment Phone: 410-955-6158
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    • Psychiatry and Behavioral Sciences - Geriatric Psychiatry and Neuropsychiatry

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